This invention refers to a device for fastening a cranial flap to the cranial vault.
As known, a craniotomy, meaning the incision and cutting out of a bone flap from the cranial vault, is a mandatory neurosurgical procedure for the treatment of any inter-cranial damage.
This procedure is generally carried out in the following manner: after properly positioning the patient depending on the intended action and planning the flap, the scalp is disinfected, the skin incising outline is drawn up and the head is covered with sterile linen.
The skin incision is performed in short sections, while controlling the hemostasis by bipolar coagulation and the application of skin clips.
After the incision has been completed, the flap of scalp is detached from the underlying pericranium, and the pericranium and muscle are incised by a diathermic cut along the intended bone flap outline, except for occasionally leaving a shaft to allow for a certain blood flow to the bone.
In certain flaps, especially those of a frontal or pterional type, the dissociation of these planes may be avoided, so as to spare the nerve endings of the facial nerve.
The bone flap is thereupon incised by drilling one or several holes, depending on whether a cutting blade or a drill bit on a pneumatic drill is applied, so that the underlying cranial vault may be detached free hand by the key hole while simultaneously incising the bone, or the hard part of the bone is dissected between one drill hole and the next by using a curved periosteum detacher. In the following, a sawing wire is guided through and pulled upward by hand at the extremities, thus excising the bone in individual segments.
The bone flap is wrapped in moist gauze and kept apart from the operating area by some fastening devices if provided with a shaft, or left free in a physiological solution in a cup.
At the end of the neurosurgical operation, after the cranial vault has been sutured and the bone edges have been turned up, the flap is refitted into the aperture and fastened with separate metal points or wires passed through small drill holes provided in pairs along the free edge of the cranial bone.
The cranial flap is occasionally left entirely free, except for a thread of silk applied on the cranial vault, passed through two drill holes and tied to the center of the bone flap.
It is nevertheless evident that solutions of this type cannot generally afford an esthetically acceptable seal, as they are not always capable of preventing the bone flap from emerging, curving, sloping or turning. In order to prevent these drawbacks, some micro-platelets made of titanium have more recently been applied by threading them in at three points on the bone flap and along the edge of the cranial vault.
Nevertheless, even this solution suffers from the fact that these micro-platelets made of titanium are not sufficiently elastic to ensure that an excess pressure will not arise on the brain during the post-operation period.
The purpose of this invention is therefore to produce a device for fastening a cranial flap to the cranial vault, capable of ensuring a correct ossification of the bone flap along the edge of the cranial vault. Another purpose of the invention is to produce a device for fastening a cranial flap to the cranial vault, capable of ensuring a lower pressure on the brain itself, even if a cerebral edema should develop during the post-operation period.
These and other purposes are achieved by a device for fastening a cranial flap to the cranial vault, according to claim 1, which is being referred to for brevity.
Other characteristics of the invention are defined in the additional claims attached to this patent application.